Decomposition of Rock Phosphate between Sodium Chloride and Water Vapor (Part 2) : On the Method of Utilizing Phosphoric Acid

Abstract

1. Ca_2P_2O_7 and Ca(PO_3)_2 (not quenched) were insoluble in 2% Citric Acid. But CaNaPO_4,and CaNa_4(PO_4)_2 which could be produced by mixing with sodium chloride and heating at 1000℃ in the water vapor atmosphere utilizing reaction between sodium chloride and water vapor were soluble in the same solutions. 2. CaNa_4(PO_4)_2 as same as Na_3PO_4,AlNa_6(PO_4)_3 decomposed Idaho phosphate rock at 1000℃ and changed to the form of 2% citric acid soluble. 3. When adding phosphoric acid to the mixtures of Idaho phospate rock and sodium chloride, so that the mol ratio of P_2O_5 : CaO : Na_2O of the whole mixtures were about 1 : 2 : 1,and heating at 1000℃ in the water vapor atmosphere, then all P_2O_5 of mixtures became 2% citric acid soluble form. 4. The mechanism of these reactions were presumed as follows : first, mixtures were made which comprised undecomposed phoshate rock , sodium chloride and monocalcium phosphate in proportion to the amount of added phosphoric acid, then on heating, monocalcium phosphate changed to metacalcium phosphate and further to CaNa_4(PO_4)_2 by sodium hydroxide which formed by the reaction between sodium chloride and water vapor, then CaNa_4(PO_4)_2 decomposed Idaho phosphate rock and the final form of phosphate in the products became CaNaPO_4 probably. 5. The manufacturing conditions of these phosphatic fertilizers utilizing reactions above mentioned and the manurial effect of these products will be reported in the next paper.